package com.nowcoder.community.service;

import com.nowcoder.community.util.RedisKeyUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.dao.DataAccessException;
import org.springframework.data.redis.connection.RedisConnection;
import org.springframework.data.redis.connection.RedisStringCommands;
import org.springframework.data.redis.core.RedisCallback;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.List;

/**
 * <p>Title: DataService</p>
 * <p>author 12427</p>
 *
 * @version ver1.0
 * @date 2022/8/23 18:21
 */
@Service
public class DataService {

    @Autowired
    private RedisTemplate redisTemplate ;

    private SimpleDateFormat df = new SimpleDateFormat("yyyyMMdd") ;

    // 将指定的IP计入UV
    public void recordUV(String ip){
        String redisKey = RedisKeyUtil.getUVKey(df.format(new Date()));
        redisTemplate.opsForHyperLogLog().add(redisKey , ip );
    }

    // 统计指定日期范围内的UV
    public long calculateUV(Date start , Date end){
        if(start == null || end == null){
            throw new IllegalArgumentException("参数不能为空") ;
        }
        // 制作一组key
        List<String> keyList = new ArrayList<>() ;

        // 日期的遍历
        Calendar calendar = Calendar.getInstance() ;
        calendar.setTime(start);
        while (!calendar.getTime().after(end)){
            keyList.add(RedisKeyUtil.getUVKey(df.format(calendar.getTime()))) ;
            calendar.add(Calendar.DATE , 1 ) ;
        }
        // 合并数据
        String redisKey = RedisKeyUtil.getUVKey(df.format(start) , df.format(end)) ;
        redisTemplate.opsForHyperLogLog().union(redisKey , keyList.toArray()) ;

        return redisTemplate.opsForHyperLogLog().size(redisKey) ;
    }


    // 将指定用户计入DAU
    public void recordDAU(int userId){
        String redisKey = RedisKeyUtil.getDAUKey(df.format(new Date())) ;
        redisTemplate.opsForValue().setBit(redisKey , userId , true) ;
    }

    // 统计指定日期范围内的DAU
    public  long calculateDAU(Date start , Date end){
        if(start == null || end == null){
            throw new IllegalArgumentException("参数不能为空") ;
        }
        // 制作一组key
        List<byte[]> keyList = new ArrayList<>() ;

        // 日期的遍历
        Calendar calendar = Calendar.getInstance() ;
        calendar.setTime(start);
        while (!calendar.getTime().after(end)){
            keyList.add(RedisKeyUtil.getDAUKey(df.format(calendar.getTime())).getBytes()) ;
            calendar.add(Calendar.DATE , 1 ) ;
        }
        // 进行or运算
        return (long) redisTemplate.execute(new RedisCallback() {
            @Override
            public Object doInRedis(RedisConnection connection) throws DataAccessException {

                String redisKey = RedisKeyUtil.getDAUKey(df.format(start) , df.format(end)) ;
                connection.bitOp(RedisStringCommands.BitOperation.OR ,
                        redisKey.getBytes() , keyList.toArray(new byte[0][0])) ;
                return connection.bitCount(redisKey.getBytes());
            }
        }) ;

    }


}
